Many personal training clients of mine notice that they lose weight while on vacation. I'm convinced that part of this is due to the fact that they tend to just eat 2-3 meals a day and little to no snacks while away.
Personally, I stopped snacking 5 or 6 years ago. Guess what happened? I found maintaining my weight (or losing, if desired) easier than ever before. There is so much less tedious planning required when you don't snack. Also, total calories, at least for many people I know, end up being much more easily controlled. And it's total calories that really wreak the most havoc on our weight. Furthermore, you learn to deal with feelings and emotions that you used to stuff down with food in other ways. Because you are forced to.
Life just gets simpler when you don't snack. And willpower becomes saved up for other tasks, because you don't always have to think, "should I eat, or should I not?" You know the answer without having to think about it. It also eliminates that mental battle of whether or not you'll grab some junk food at a sporting event or at the movies, or even in your car while driving around. You'll also save money :)
The average American consumes 650 calories worth of snacks EACH DAY - most of it in the form of processed foods. For some adults, that is over 1/3 of a day's total calories, and that's only if you are trying to maintain your weight, not lose! It didn't used to be this way.